Regensburg 2000 – wissenschaftliches Programm
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AM: Magnetismus
AM 11: Dünne Schichten II: Austauschkopplung
AM 11.5: Vortrag
Dienstag, 28. März 2000, 15:15–15:30, H10
Epitaxial Fe/Si/Fe layers – structure and magnetism — •Jürgen Kohlhepp1, Gustav Strijkers1,2, Henk Swagten1, and Wim de Jonge1 — 1Department of Applied Physics, Eindhoven University of Technology, The Netherlands — 2Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, USA
Fe/Si/Fe sandwich systems epitaxially grown on clean Ge(100) by MBE feature a number of both structural as well as magnetic interesting and unique properties: A bcc-like (100) structure is maintained throughout the layers after the recrystallization of the spacer into a metastable iron-silicide phase with a CsCl structure triggered by Fe/Si interdiffusion during the growth. Both bilinear as well as biquadratic magnetic interlayer exchange coupling are observed with a rather exceptional behaviour, their strengths decay exponentially with the nominal Si spacer layer thickness, in contrast to the usually observed oscillatory behaviour. Furthermore, the biquadratic exchange shows a strong temperature dependence whereas the bilinear coupling is almost temperature independent. While the bilinear coupling is an intrinsic effect caused by the high density of states peak above the Fermi level of the iron-silicide spacer, the biquadratic exchange is extrinsic in nature and can be understood by so-called loose spins in the spacer layer.